Irregulars using human shields to approach British forces, firing, and then running back into city.
Briefing officer says he won't say much about disposition of forces or operations.
Main thrust is humanitarian relief, especially water.
Briefing officer says Iraqis may be reinforcing from the north of the city, but believe most fighters are fedayeen and remnants of the 51st Division
Rear-area security has been tightened up significantly